1. Field of the Invention
The present invention relates to a surgical instrument comprising: an insert section inserted into a patient's body; a manipulating section provided at a proximal end section of the insert section and gripped by a surgeon; and a tool section provided at a distal end of the insert section and articulated and opened/closed by the manipulating section.
2. Description of the Related Art
Surgical instruments carrying out surgical operation are disclosed in U.S. Pat. Nos. 5,275,608, 5,702,408, 5,383,888, and 4,763,669.
The surgical instrument disclosed in U.S. Pat. No. 5,275,608 is composed of: a shaft, an openable/closable tool section provided at a proximal end section of this shaft; and a handle provided at a distal end section of the shaft. The tool section is composed so that it can be articulated in the same plane by means of a handle manipulation other than an opening/closing manipulation.
The surgical instrument disclosed in U.S. Pat. No. 5,702,408 comprises: a link lever shaped first link; and second and third links connected to the first link, wherein the second and third links can be moved inwardly each other, and a fourth link is connected to both link end sections. The tool section and manipulating section are set at the same angle by means of a parallel link mechanism for articulating the first link in a first direction and articulating the fourth link in the first direction.
The surgical instrument disclosed in U.S. Pat. No. 5,383,888 is composed of: a shaft; an openable/closable and articulable tool section provided at the proximal end section of this shaft; and a handle provided at the distal end section of the shaft. A tool section is opened/closed by a handle manipulation, and a manipulating wire is advanced/retracted by a lever provided at the handle side, whereby the tool section is articulated.
The surgical instrument disclosed in U.S. Pat. No. 4,763,669 is composed of a shaft; an openable/closable and articulable tool section provided at the distal end section of this shaft; and a handle provided at the proximal end section of the shaft. The tool section is opened/closed by the handle manipulation, and a push rod is advanced/retracted by a lever provided at a handle side, whereby the tool section is articulated.
However, almost of the previously-described conventional surgical instrument is articulated on only a single plane. Thus, in particular, when a complicated manipulation for suturing/ligating tissues is achieved, the degree of freedom for articulating is insufficient.
The previously-described surgical instrument can articulate and rotate the tool section from the manipulating section side. However, while a single thumb and fingers other than the thumb are hooked on the manipulating section, it is difficult to turn the tool section and approach it to a target site by manipulation using the same one hand and to close and open the tool section at the target site. Thus, it is difficult to divert the previously-described surgical instrument for suturing and ligating. In actuality, there does not exist a surgical instrument suitable for suturing/ligating, the surgical instrument being capable of being articulated in an arbitrary direction and being capable of being opened/closed by one hand.
The previously-described surgical instrument disclosed in U.S. Pat. No. 5,272,608 basically has a link in which the manipulating section and tool section move at an equal angle. However, a link composed of: a manipulating section side member made of a disk having a fixed rotary shaft at its center; a main shaft and a movable shaft parallel to this main shaft; and a tool section side member having a fixed rotary shaft at its center, is housed in an insert shaft at its proximal end side. Thus, in fact, the effective width of the manipulating section side member cannot be set to a necessary and sufficient value. In addition, an articulating torque generated by articulating of the manipulating section cannot be sufficiently obtained. Further, the main shaft extends the center of the insert section. Thus, a substantial link width is reduced, and similar effect is considered. U.S. Pat. No. 5,275,608 discusses only articulating on one plane. An articulating ratio between the manipulating section side member and tool section side member cannot be set in a plurality of articulating planes, or alternatively, an articulating manipulation cannot be executed. A flexible member is used for an opening/closing mechanism in order to cope with displacement of a mechanism caused by an articulating manipulation. As a result, the required opening/closing gripping force and direct manipulation may be degraded.
An articulating mechanism caused by a parallel link is disclosed in the previously-described U.S. Pat. No. 5,702,408. However, a mechanism for opening/closing manipulation is not suggested, and an embodiment of the surgical instrument having an equal articulating angle at the manipulating section side and at the tool section side is merely disclosed. In the art disclosed in U.S. Pat. No. 5,702,408, the manipulating section and tool section are connected to each other by means of a simple pair of links, and thus, the entire link is moved in a diameter direction of the insert section by manipulation of the manipulating section. Therefore, a sufficient space is required so that a link does not interfere with an internal hole of the insert section. As a result, there is a problem that the insert section is increased in diameter. When the link is long, an error easily occurs between an articulating manipulation quantity of the manipulating section and articulating movement quantity of the tool section due to slackness of the link itself.
A general problem in the previously-described prior art is that, when the tool section is set into the desirable articulating state by articulating the manipulating section, if a surgeon turns a manipulating section excessively, or if a surgeon articulates a manipulating section with an excessive force, the tool section may be deformed or destroyed so that a normal operation may be failed.
In general, when tissues are ligated by the surgical instrument, a so-called thread manipulation of surgical ligation or the like, for winding a suture thread connected to a suture needle around the surgical instrument for manipulating it, is carried out. However, a transmission member such as link for transmitting manipulation of the manipulating section to the tool section is articulably connected to the insert section each other by a pivot pin. In general, a step is generated at a connecting section between the transmission members. Thus, the suture thread is hooked on the step, and there is a possibility that smooth ligating manipulation is inhibited.